//
//  CJSONScanner.m
//  TouchCode
//
//  Created by Jonathan Wight on 12/07/2005.
//  Copyright 2005 toxicsoftware.com. All rights reserved.
//
//  Permission is hereby granted, free of charge, to any person
//  obtaining a copy of this software and associated documentation
//  files (the "Software"), to deal in the Software without
//  restriction, including without limitation the rights to use,
//  copy, modify, merge, publish, distribute, sublicense, and/or sell
//  copies of the Software, and to permit persons to whom the
//  Software is furnished to do so, subject to the following
//  conditions:
//
//  The above copyright notice and this permission notice shall be
//  included in all copies or substantial portions of the Software.
//
//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
//  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
//  OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
//  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
//  HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
//  WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
//  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
//  OTHER DEALINGS IN THE SOFTWARE.
//

#import "CJSONScanner.h"

#import "NSCharacterSet_Extensions.h"
#import "CDataScanner_Extensions.h"

#if !defined(TREAT_COMMENTS_AS_WHITESPACE)
#define TREAT_COMMENTS_AS_WHITESPACE 0
#endif // !defined(TREAT_COMMENTS_AS_WHITESPACE)

NSString *const kJSONScannerErrorDomain = @"CJSONScannerErrorDomain";

inline static int HexToInt(char inCharacter)
{
    int theValues[] = { 0x0 /* 48 '0' */, 0x1 /* 49 '1' */, 0x2 /* 50 '2' */, 0x3 /* 51 '3' */, 0x4 /* 52 '4' */, 0x5 /* 53 '5' */, 0x6 /* 54 '6' */, 0x7 /* 55 '7' */, 0x8 /* 56 '8' */, 0x9 /* 57 '9' */, -1 /* 58 ':' */, -1 /* 59 ';' */, -1 /* 60 '<' */, -1 /* 61 '=' */, -1 /* 62 '>' */, -1 /* 63 '?' */, -1 /* 64 '@' */, 0xa /* 65 'A' */, 0xb /* 66 'B' */, 0xc /* 67 'C' */, 0xd /* 68 'D' */, 0xe /* 69 'E' */, 0xf /* 70 'F' */, -1 /* 71 'G' */, -1 /* 72 'H' */, -1 /* 73 'I' */, -1 /* 74 'J' */, -1 /* 75 'K' */, -1 /* 76 'L' */, -1 /* 77 'M' */, -1 /* 78 'N' */, -1 /* 79 'O' */, -1 /* 80 'P' */, -1 /* 81 'Q' */, -1 /* 82 'R' */, -1 /* 83 'S' */, -1 /* 84 'T' */, -1 /* 85 'U' */, -1 /* 86 'V' */, -1 /* 87 'W' */, -1 /* 88 'X' */, -1 /* 89 'Y' */, -1 /* 90 'Z' */, -1 /* 91 '[' */, -1 /* 92 '\' */, -1 /* 93 ']' */, -1 /* 94 '^' */, -1 /* 95 '_' */, -1 /* 96 '`' */, 0xa /* 97 'a' */, 0xb /* 98 'b' */, 0xc /* 99 'c' */, 0xd /* 100 'd' */, 0xe /* 101 'e' */, 0xf /* 102 'f' */, };
    if (inCharacter >= '0' && inCharacter <= 'f')
        return(theValues[inCharacter - '0']);
    else
        return(-1);
}

@interface CJSONScanner ()
- (BOOL)scanNotQuoteCharactersIntoString:(NSString **)outValue;
@end

#pragma mark -

@implementation CJSONScanner

@synthesize strictEscapeCodes;

- (id)init
{
    if ((self = [super init]) != nil)
	{
        strictEscapeCodes = NO;
	}
    return(self);
}

- (void)dealloc
{
    //
    [super dealloc];
}

#pragma mark -

- (void)setData:(NSData *)inData
{
    NSData *theData = inData;
    if (theData && theData.length >= 4)
	{
        // This code is lame, but it works. Because the first character of any JSON string will always be a (ascii) control character we can work out the Unicode encoding by the bit pattern. See section 3 of http://www.ietf.org/rfc/rfc4627.txt
        const char *theChars = theData.bytes;
        NSStringEncoding theEncoding = NSUTF8StringEncoding;
        if (theChars[0] != 0 && theChars[1] == 0)
		{
            if (theChars[2] != 0 && theChars[3] == 0)
                theEncoding = NSUTF16LittleEndianStringEncoding;
            else if (theChars[2] == 0 && theChars[3] == 0)
                theEncoding = NSUTF32LittleEndianStringEncoding;
		}
        else if (theChars[0] == 0 && theChars[2] == 0 && theChars[3] != 0)
		{
            if (theChars[1] == 0)
                theEncoding = NSUTF32BigEndianStringEncoding;
            else if (theChars[1] != 0)
                theEncoding = NSUTF16BigEndianStringEncoding;
		}
		
        if (theEncoding != NSUTF8StringEncoding)
		{
            NSString *theString = [[NSString alloc] initWithData:theData encoding:theEncoding];
            theData = [theString dataUsingEncoding:NSUTF8StringEncoding];
            [theString release];
		}
	}
    [super setData:theData];
}

#pragma mark -

- (BOOL)scanJSONObject:(id *)outObject error:(NSError **)outError
{
    BOOL theResult = YES;
    
    [self skipWhitespace];
    
    id theObject = NULL;
    
    const unichar C = [self currentCharacter];
    switch (C)
	{
        case 't':
            if ([self scanUTF8String:"true" intoString:NULL])
			{
                theObject = [NSNumber numberWithBool:YES];
			}
            break;
        case 'f':
            if ([self scanUTF8String:"false" intoString:NULL])
			{
                theObject = [NSNumber numberWithBool:NO];
			}
            break;
        case 'n':
            if ([self scanUTF8String:"null" intoString:NULL])
			{
                theObject = [NSNull null];
			}
            break;
        case '\"':
        case '\'':
            theResult = [self scanJSONStringConstant:&theObject error:outError];
            break;
        case '0':
        case '1':
        case '2':
        case '3':
        case '4':
        case '5':
        case '6':
        case '7':
        case '8':
        case '9':
        case '-':
            theResult = [self scanJSONNumberConstant:&theObject error:outError];
            break;
        case '{':
            theResult = [self scanJSONDictionary:&theObject error:outError];
            break;
        case '[':
            theResult = [self scanJSONArray:&theObject error:outError];
            break;
        default:
            
            break;
	}
    
    if (outObject != NULL)
        *outObject = theObject;
    
    return(theResult);
}

- (BOOL)scanJSONDictionary:(NSDictionary **)outDictionary error:(NSError **)outError
{
    NSUInteger theScanLocation = [self scanLocation];
    
    if ([self scanCharacter:'{'] == NO)
	{
        if (outError)
		{
            NSDictionary *theUserInfo = [NSDictionary dictionaryWithObjectsAndKeys:
                                         @"Could not scan dictionary. Dictionary that does not start with '{' character.", NSLocalizedDescriptionKey,
                                         NULL];
            *outError = [NSError errorWithDomain:kJSONScannerErrorDomain code:-1 userInfo:theUserInfo];
		}
        return(NO);
	}
    
    NSMutableDictionary *theDictionary = [[NSMutableDictionary alloc] init];
    
    while ([self currentCharacter] != '}')
	{
        [self skipWhitespace];
        
        if ([self currentCharacter] == '}')
            break;
        
        NSString *theKey = NULL;
        if ([self scanJSONStringConstant:&theKey error:outError] == NO)
		{
            [self setScanLocation:theScanLocation];
            if (outError)
			{
                NSDictionary *theUserInfo = [NSDictionary dictionaryWithObjectsAndKeys:
                                             @"Could not scan dictionary. Failed to scan a key.", NSLocalizedDescriptionKey,
                                             NULL];
                *outError = [NSError errorWithDomain:kJSONScannerErrorDomain code:-2 userInfo:theUserInfo];
			}
            [theDictionary release];
            return(NO);
		}
        
        [self skipWhitespace];
        
        if ([self scanCharacter:':'] == NO)
		{
            [self setScanLocation:theScanLocation];
            if (outError)
			{
                NSDictionary *theUserInfo = [NSDictionary dictionaryWithObjectsAndKeys:
                                             @"Could not scan dictionary. Key was not terminated with a ':' character.", NSLocalizedDescriptionKey,
                                             NULL];
                *outError = [NSError errorWithDomain:kJSONScannerErrorDomain code:-3 userInfo:theUserInfo];
			}
            [theDictionary release];
            return(NO);
		}
        
        id theValue = NULL;
        if ([self scanJSONObject:&theValue error:outError] == NO)
		{
            [self setScanLocation:theScanLocation];
            if (outError)
			{
                NSDictionary *theUserInfo = [NSDictionary dictionaryWithObjectsAndKeys:
                                             @"Could not scan dictionary. Failed to scan a value.", NSLocalizedDescriptionKey,
                                             NULL];
                *outError = [NSError errorWithDomain:kJSONScannerErrorDomain code:-4 userInfo:theUserInfo];
			}
            [theDictionary release];
            return(NO);
		}
        
        [theDictionary setValue:theValue forKey:theKey];
        
        [self skipWhitespace];
        if ([self scanCharacter:','] == NO)
		{
            if ([self currentCharacter] != '}')
			{
                [self setScanLocation:theScanLocation];
                if (outError)
				{
                    NSDictionary *theUserInfo = [NSDictionary dictionaryWithObjectsAndKeys:
                                                 @"Could not scan dictionary. Key value pairs not delimited with a ',' character.", NSLocalizedDescriptionKey,
                                                 NULL];
                    *outError = [NSError errorWithDomain:kJSONScannerErrorDomain code:-5 userInfo:theUserInfo];
				}
                [theDictionary release];
                return(NO);
			}
            break;
		}
        else
		{
            [self skipWhitespace];
            if ([self currentCharacter] == '}')
                break;
		}
	}
    
    if ([self scanCharacter:'}'] == NO)
	{
        [self setScanLocation:theScanLocation];
        if (outError)
		{
            NSDictionary *theUserInfo = [NSDictionary dictionaryWithObjectsAndKeys:
                                         @"Could not scan dictionary. Dictionary not terminated by a '}' character.", NSLocalizedDescriptionKey,
                                         NULL];
            *outError = [NSError errorWithDomain:kJSONScannerErrorDomain code:-6 userInfo:theUserInfo];
		}
        [theDictionary release];
        return(NO);
	}
    
    if (outDictionary != NULL)
        *outDictionary = [[theDictionary copy] autorelease];
    
    [theDictionary release];
    
    return(YES);
}

- (BOOL)scanJSONArray:(NSArray **)outArray error:(NSError **)outError
{
    NSUInteger theScanLocation = [self scanLocation];
    
    if ([self scanCharacter:'['] == NO)
	{
        if (outError)
		{
            NSDictionary *theUserInfo = [NSDictionary dictionaryWithObjectsAndKeys:
                                         @"Could not scan array. Array not started by a '{' character.", NSLocalizedDescriptionKey,
                                         NULL];
            *outError = [NSError errorWithDomain:kJSONScannerErrorDomain code:-7 userInfo:theUserInfo];
		}
        return(NO);
	}
    
    NSMutableArray *theArray = [[NSMutableArray alloc] init];
    
    [self skipWhitespace];
    while ([self currentCharacter] != ']')
	{
        NSString *theValue = NULL;
        if ([self scanJSONObject:&theValue error:outError] == NO)
		{
            [self setScanLocation:theScanLocation];
            if (outError)
			{
                NSDictionary *theUserInfo = [NSDictionary dictionaryWithObjectsAndKeys:
                                             @"Could not scan array. Could not scan a value.", NSLocalizedDescriptionKey,
                                             NULL];
                *outError = [NSError errorWithDomain:kJSONScannerErrorDomain code:-8 userInfo:theUserInfo];
			}
            [theArray release];
            return(NO);
		}
        
        [theArray addObject:theValue];
        
        [self skipWhitespace];
        if ([self scanCharacter:','] == NO)
		{
            [self skipWhitespace];
            if ([self currentCharacter] != ']')
			{
                [self setScanLocation:theScanLocation];
                if (outError)
				{
                    NSDictionary *theUserInfo = [NSDictionary dictionaryWithObjectsAndKeys:
                                                 @"Could not scan array. Array not terminated by a ']' character.", NSLocalizedDescriptionKey,
                                                 NULL];
                    *outError = [NSError errorWithDomain:kJSONScannerErrorDomain code:-9 userInfo:theUserInfo];
				}
                [theArray release];
                return(NO);
			}
            
            break;
		}
        [self skipWhitespace];
	}
    
    [self skipWhitespace];
    
    if ([self scanCharacter:']'] == NO)
	{
        [self setScanLocation:theScanLocation];
        if (outError)
		{
            NSDictionary *theUserInfo = [NSDictionary dictionaryWithObjectsAndKeys:
                                         @"Could not scan array. Array not terminated by a ']' character.", NSLocalizedDescriptionKey,
                                         NULL];
            *outError = [NSError errorWithDomain:kJSONScannerErrorDomain code:-10 userInfo:theUserInfo];
		}
        [theArray release];
        return(NO);
	}
    
    if (outArray != NULL)
        *outArray = [[theArray copy] autorelease];
    
    [theArray release];
    
    return(YES);
}

- (BOOL)scanJSONStringConstant:(NSString **)outStringConstant error:(NSError **)outError
{
    NSUInteger theScanLocation = [self scanLocation];
    
    [self skipWhitespace]; //  TODO - i want to remove this method. But breaks unit tests.
    
    NSMutableString *theString = [[NSMutableString alloc] init];
    
    if ([self scanCharacter:'"'] == NO)
	{
        [self setScanLocation:theScanLocation];
        if (outError)
		{
            NSDictionary *theUserInfo = [NSDictionary dictionaryWithObjectsAndKeys:
                                         @"Could not scan string constant. String not started by a '\"' character.", NSLocalizedDescriptionKey,
                                         NULL];
            *outError = [NSError errorWithDomain:kJSONScannerErrorDomain code:-11 userInfo:theUserInfo];
		}
        [theString release];
        return(NO);
	}
    
    while ([self scanCharacter:'"'] == NO)
	{
        NSString *theStringChunk = NULL;
        if ([self scanNotQuoteCharactersIntoString:&theStringChunk])
		{
//          NSLog(@"%@",theStringChunk);
            if(!theStringChunk.length)
            {
                break;
//                theStringChunk = @"";
//                NSLog(@"dsfgsd");
//                NSLog(@"dfsg sdg");
            }
            [theString appendString:theStringChunk];
		}
        
        if ([self scanCharacter:'\\'] == YES)
		{
            unichar theCharacter = [self scanCharacter];
            switch (theCharacter)
			{
                case '"':
                case '\\':
                case '/':
                    break;
                case 'b':
                    theCharacter = '\b';
                    break;
                case 'f':
                    theCharacter = '\f';
                    break;
                case 'n':
                    theCharacter = '\n';
                    break;
                case 'r':
                    theCharacter = '\r';
                    break;
                case 't':
                    theCharacter = '\t';
                    break;
                case 'u':
				{
                    theCharacter = 0;
                    int theShift;
                    for (theShift = 12; theShift >= 0; theShift -= 4)
					{
                        const int theDigit = HexToInt([self scanCharacter]);
                        if (theDigit == -1)
						{
                            [self setScanLocation:theScanLocation];
                            if (outError)
							{
                                NSDictionary *theUserInfo = [NSDictionary dictionaryWithObjectsAndKeys:
                                                             @"Could not scan string constant. Unicode character could not be decoded.", NSLocalizedDescriptionKey,
                                                             NULL];
                                *outError = [NSError errorWithDomain:kJSONScannerErrorDomain code:-12 userInfo:theUserInfo];
							}
                            [theString release];
                            return(NO);
						}
                        theCharacter |= (theDigit << theShift);
					}
				}
                    break;
                default:
				{
                
                    if (strictEscapeCodes == YES)
					{
                        [self setScanLocation:theScanLocation];
                        if (outError)
						{
                            NSDictionary *theUserInfo = [NSDictionary dictionaryWithObjectsAndKeys:
                                                         @"Could not scan string constant. Unknown escape code.", NSLocalizedDescriptionKey,
                                                         NULL];
                            *outError = [NSError errorWithDomain:kJSONScannerErrorDomain code:-13 userInfo:theUserInfo];
						}
                        [theString release];
                        return(NO);
					}
				}
                    break;
			}
            CFStringAppendCharacters((CFMutableStringRef)theString, &theCharacter, 1);
		}
	}
	
    if (outStringConstant != NULL)
        *outStringConstant = [[theString mutableCopy] autorelease];
    
    [theString release];
    
    return(YES);
}

- (BOOL)scanJSONNumberConstant:(NSNumber **)outNumberConstant error:(NSError **)outError
{
    NSNumber *theNumber = NULL;
    if ([self scanNumber:&theNumber] == YES)
	{
        if (outNumberConstant != NULL)
            *outNumberConstant = theNumber;
        return(YES);
	}
    else
	{
        if (outError)
		{
            NSDictionary *theUserInfo = [NSDictionary dictionaryWithObjectsAndKeys:
                                         @"Could not scan number constant.", NSLocalizedDescriptionKey,
                                         NULL];
            *outError = [NSError errorWithDomain:kJSONScannerErrorDomain code:-14 userInfo:theUserInfo];
		}
        return(NO);
	}
}

#if TREAT_COMMENTS_AS_WHITESPACE
- (void)skipWhitespace
{
    [super skipWhitespace];
    [self scanCStyleComment:NULL];
    [self scanCPlusPlusStyleComment:NULL];
    [super skipWhitespace];
}
#endif // TREAT_COMMENTS_AS_WHITESPACE

#pragma mark -

- (BOOL)scanNotQuoteCharactersIntoString:(NSString **)outValue
{
    u_int8_t *P;
    for (P = current; P < end && *P != '\"' && *P != '\\'; ++P)
        ;
    
    if (P == current)
	{
        return(NO);
	}
    
    if (outValue)
	{
        *outValue = [[[NSString alloc] initWithBytes:current length:P - current encoding:NSUTF8StringEncoding] autorelease];
	}
	
    current = P;
    
    return(YES);
}

@end
